Proteolytic, lipolytic and molecular characterisation of Yarrowia lipolytica isolated from cheese

This work studied the qualitative and quantitative proteolytic and lipolyti c activities of Yarrowia lipolytica strains isolated from two cheese types. Randomly amplified polymorphic DNA-PCR (RAPD-PCR) analysis was used to com pare the cheese strains of Y. lipolytica with strains isolated from other f ood products and with the type strain of the species in order to investigat e the genetic diversity and occurrence of specific environmental groups. Diversity of proteolytic and especially lipolytic activity within Y. lipoly tica strains isolated from dairy products was observed. In particular, the degree of specificity for saturated or unsaturated fatty acids as well as f or even- or odd-numbered carbon free fatty acids (FFAs) varied among the st rains. The RAPD-PCR profiles showed low genetic relatedness between many of the food isolates and the type strain of the species. Such genetic variabi lity needs to be further evaluated. Most of the Y. lipolytica strains appea red to be specific to the particular environment from which they were isola ted. However, phenotypic characteristics having technological importance in dairy products and, particularly, lipolytic activities did not correspond to the genetic differences observed by RAPD-PCR analysis. (C) 2001 Elsevier Science B.V.. All rights reserved.